1. Field of the Invention
The present invention relates to a lead wire bonding method for bonding a lead wire having a bent portion to a printed circuit board.
2. Description of the Background Art
As the lead wire bonding method for bonding a lead wire having a bent portion to a printed circuit board, there are various techniques. For example, the Patent Document 1 (Japanese Patent No. 2768141) shows a technique using laser beam welding.
If a lead wire has a bent portion, even in circumstances with heavy vibration, the bent portion of the lead wire absorbs the vibration to decrease bonding failure of the lead wire.
In the above Patent Document 1, as shown in FIG. 9, disclosed is a technique in which a pad 3 on a substrate 6 and a terminal 2 provided in a case 4 are connected to each other with a lead wire 5.
In the lead wire bonding method of the above Patent Document 1, however, formation of a bent portion of the lead wire and welding of the lead wire to the substrate must be performed in a narrow space of the case 4 and this requires complicated operations of a molding pin 86 and a welding nozzle 41. Therefore, the lead wire bonding operation becomes complicated and this increases time for manufacture and decreases yield due to bonding failure.